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<a href="timer__ev__emitter_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow-IPC: Core</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno">    8</span><span class="comment"> *</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno">    9</span><span class="comment"> *   https://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno">   10</span><span class="comment"> *</span></div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno">   11</span><span class="comment"> * Unless required by applicable law or agreed to in</span></div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno">   12</span><span class="comment"> * writing, software distributed under the License is</span></div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno">   13</span><span class="comment"> * distributed on an &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR</span></div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno">   14</span><span class="comment"> * CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno">   15</span><span class="comment"> * See the License for the specific language governing</span></div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span><span class="preprocessor">#pragma once</span></div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span> </div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span><span class="preprocessor">#include &quot;<a class="code" href="util__fwd_8hpp.html">ipc/util/util_fwd.hpp</a>&quot;</span></div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span><span class="preprocessor">#include &lt;flow/async/single_thread_task_loop.hpp&gt;</span></div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span> </div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceipc_1_1util_1_1sync__io.html">ipc::util::sync_io</a></div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span>{</div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span><span class="comment"></span> </div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span><span class="comment">/**</span></div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno">   28</span><span class="comment"> * An object of this type, used internally to implement `sync_io`-pattern objects that require timer events,</span></div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span><span class="comment"> * starts a thread dedicated exclusively to running timer waits on the `sync_io` object&#39;s behalf, so that when</span></div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span><span class="comment"> * such a timer fires, it emits a pipe-readable event to be detected by the user&#39;s event loop, which it then reports to</span></div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno">   31</span><span class="comment"> * `sync_io` object.</span></div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span><span class="comment"> *</span></div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno">   33</span><span class="comment"> * @see ipc::util::sync_io for discussion of the `sync_io` pattern.  This is necessary background for the present</span></div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span><span class="comment"> *      class which is used in implementing objects within that pattern.</span></div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span><span class="comment"> *</span></div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span><span class="comment"> * ### Rationale ###</span></div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span><span class="comment"> * In the `sync_io` pattern, suppose there is ipc::transport or ipc::session object X (e.g.,</span></div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span><span class="comment"> * ipc::transport::sync_io::Native_socket_stream::Impl).  By definiton of the `sync_io` pattern, X itself</span></div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span><span class="comment"> * endeavours to not async-wait on various events itself, in its own threads it might start, but rather</span></div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span><span class="comment"> * instructs the user to wait on Native_handle being readable or writable and to inform X of such an event</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span><span class="comment"> * (see sync_io::Event_wait_func doc header).  For example `Native_socket_stream::Impl`, when awaiting in-traffic,</span></div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span><span class="comment"> * uses #Event_wait_func to inform itself when the Unix-domain socket has become readable -- the user uses</span></div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno">   43</span><span class="comment"> * their own `[e]poll*()` or boost.asio loop or ... to detect the readability and then informs X when this happens.</span></div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span><span class="comment"> *</span></div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span><span class="comment"> * Some objects, in particular at least various `Blob_receiver`s and `Blob_sender`s, also at times wait on</span></div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span><span class="comment"> * timer events; in implementing transport::Blob_receiver::idle_timer_run() and transport::Blob_sender::auto_ping()</span></div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno">   47</span><span class="comment"> * respectively.  For example if the idle timer fires, then `Blob_receiver` X needs to know; and if there is</span></div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span><span class="comment"> * an outstanding `Blob_receiver::async_receive_blob()`, it should not continue being outstanding but rather:</span></div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span><span class="comment"> * (1) The user&#39;s event loop -- which might otherwise be in the middle of a blocking `epoll_wait()` -- must</span></div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span><span class="comment"> * exit any such wait; and (2) X should be informed, in this case so the outstanding receive-op would complete</span></div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno">   51</span><span class="comment"> * with the idle-timeout error, detectable by the user&#39;s event loop before the next `epoll_wait()`.</span></div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span><span class="comment"> *</span></div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno">   53</span><span class="comment"> * But how to even accompish (1)?  ((2) is relatively simple in comparison.)  Possibilities:</span></div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span><span class="comment"> *   - The user can be told of the next-soonest timer&#39;s expiration time, so that the `epoll_wait()` (or `poll()` or</span></div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span><span class="comment"> *     ...) can be set to time out at that time, latest.</span></div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span><span class="comment"> *     - This is viable but presents a tricky API design problem for the `sync_io` pattern.  The next-soonest</span></div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span><span class="comment"> *       timer expiration time will change over time, as new timers pop or existing timers are rescheduled.</span></div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno">   58</span><span class="comment"> *       #Event_wait_func semantics have to be expanded beyond us specifying a mere (FD, read-vs-write flag)</span></div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno">   59</span><span class="comment"> *       pair; it would now specify a timer, and somehow the next-soonest timer across *all* `sync_io` objects</span></div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span><span class="comment"> *       in use by the user (not just X alone) would need to be computable.  Doable but much more complex</span></div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno">   61</span><span class="comment"> *       than a set of decoupled FD+flag pairs, one per #Event_wait_func invocation.</span></div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span><span class="comment"> *   - The OS can be somehow told to tickle a dedicated-to-this-purpose FD (per timer) at a particular time,</span></div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno">   63</span><span class="comment"> *     while #Event_wait_func is used (same as it is for Unix domain sockets, etc.) to wait for readability of</span></div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno">   64</span><span class="comment"> *     that FD.  `epoll_wait()` (or ...) would wake up like on any other event and inform X, and X would even</span></div>
<div class="line"><a id="l00065" name="l00065"></a><span class="lineno">   65</span><span class="comment"> *     know which timer it is, by being informed via `Event_wait_func`&#39;s&#39; `on_active_ev_func` arg.</span></div>
<div class="line"><a id="l00066" name="l00066"></a><span class="lineno">   66</span><span class="comment"> *</span></div>
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno">   67</span><span class="comment"> * The latter option is much more attractive in terms of API simplicity from the user&#39;s point of view (at least).</span></div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno">   68</span><span class="comment"> * So we go with that.  Having make this decision, how to actually make it work?  Possibilities:</span></div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno">   69</span><span class="comment"> *   - The OS has these mechanisms.  Linux, at least, has `timerfd_create()` and buddies, specifically for this.</span></div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno">   70</span><span class="comment"> *     One can schedule a timer, so the kernel keeps track of all that and does it in the background; when</span></div>
<div class="line"><a id="l00071" name="l00071"></a><span class="lineno">   71</span><span class="comment"> *     ready the FD becomes readable.  Done.</span></div>
<div class="line"><a id="l00072" name="l00072"></a><span class="lineno">   72</span><span class="comment"> *     - This is a very reasonable approach.  However it is not very portable, and the API is hairy enough to</span></div>
<div class="line"><a id="l00073" name="l00073"></a><span class="lineno">   73</span><span class="comment"> *       require a bunch of (internal to us) wrapping code: specifying the time along the proper clock,</span></div>
<div class="line"><a id="l00074" name="l00074"></a><span class="lineno">   74</span><span class="comment"> *       rescheduling, canceling....</span></div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno">   75</span><span class="comment"> *   - boost.asio, of course, has `flow::util::Timer` (a/k/a `waitable_timer`).  `Timer::async_wait(F)` starts</span></div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno">   76</span><span class="comment"> *     a wait, invoking `F` in whatever thread(s) are running the `Timer`&#39;s attached `Task_engine`</span></div>
<div class="line"><a id="l00077" name="l00077"></a><span class="lineno">   77</span><span class="comment"> *     (a/k/a `io_context`); `Timer::expires_after()` (re)schedules the timer; etc.</span></div>
<div class="line"><a id="l00078" name="l00078"></a><span class="lineno">   78</span><span class="comment"> *     - This is a much nicer API, and it is portable and oft-used in the Flow world.  The only problem is it</span></div>
<div class="line"><a id="l00079" name="l00079"></a><span class="lineno">   79</span><span class="comment"> *       is not attached -- in a public way -- to any particular FD.  Although boost.asio source shows</span></div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno">   80</span><span class="comment"> *       internally `timerfd_create()` is used (at least when certain compile-time flags are set),</span></div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno">   81</span><span class="comment"> *       there&#39;s no `Timer::native_handle()` that exposes the timer FD.  That said `F()` can do whatever we</span></div>
<div class="line"><a id="l00082" name="l00082"></a><span class="lineno">   82</span><span class="comment"> *       want... including pinging some simple (internally-setup) IPC mechanism, like an anonymous pipe,</span></div>
<div class="line"><a id="l00083" name="l00083"></a><span class="lineno">   83</span><span class="comment"> *       whose read-end is accessed via an FD.</span></div>
<div class="line"><a id="l00084" name="l00084"></a><span class="lineno">   84</span><span class="comment"> *</span></div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno">   85</span><span class="comment"> * Bottom line, we went with the latter approach.  It is more elegant.  It does, however, require two things</span></div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno">   86</span><span class="comment"> * which the kernel-timer approach does not:</span></div>
<div class="line"><a id="l00087" name="l00087"></a><span class="lineno">   87</span><span class="comment"> *   - The IPC mechanism.  We use a pipe (per timer).  boost.asio even provides portable support for this.</span></div>
<div class="line"><a id="l00088" name="l00088"></a><span class="lineno">   88</span><span class="comment"> *   - A background thread in which `F()` would write a byte to this pipe, when the timer fires.</span></div>
<div class="line"><a id="l00089" name="l00089"></a><span class="lineno">   89</span><span class="comment"> *     - Threads are easy to set up for us.  Isn&#39;t this a performance problem though?  Answer: No; at least not</span></div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno">   90</span><span class="comment"> *       in our use case.  The overhead is in 1, the context switch *at the time a timer actually fires* and</span></div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno">   91</span><span class="comment"> *       2, the pipe write and resulting read.  These theoretically add latency but *only* when a timer</span></div>
<div class="line"><a id="l00092" name="l00092"></a><span class="lineno">   92</span><span class="comment"> *       fires.  If we were using timers for something frequent -- like, I don&#39;t know, packet pacing -- this</span></div>
<div class="line"><a id="l00093" name="l00093"></a><span class="lineno">   93</span><span class="comment"> *       would be an issue.  We do not: idle timers and auto-ping timers fire at worst seconds apart.</span></div>
<div class="line"><a id="l00094" name="l00094"></a><span class="lineno">   94</span><span class="comment"> *       There is no real latency impact there over time.</span></div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno">   95</span><span class="comment"> *</span></div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno">   96</span><span class="comment"> * So there you have it.  We need:</span></div>
<div class="line"><a id="l00097" name="l00097"></a><span class="lineno">   97</span><span class="comment"> *   - A thread for 1+ timers.  E.g., typically, one object X would require one thread for all its timers.</span></div>
<div class="line"><a id="l00098" name="l00098"></a><span class="lineno">   98</span><span class="comment"> *   - An unnamed pipe per timer.  The thread would write to the write end, while object X would read from</span></div>
<div class="line"><a id="l00099" name="l00099"></a><span class="lineno">   99</span><span class="comment"> *     the read end and give the read-end FD to the user to wait-on via #Event_wait_func.</span></div>
<div class="line"><a id="l00100" name="l00100"></a><span class="lineno">  100</span><span class="comment"> *   - Some simple logic such that when a given timer fires, the handler (in the aforementioned thread)</span></div>
<div class="line"><a id="l00101" name="l00101"></a><span class="lineno">  101</span><span class="comment"> *     merely writes a byte to the associated pipe.</span></div>
<div class="line"><a id="l00102" name="l00102"></a><span class="lineno">  102</span><span class="comment"> *</span></div>
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno">  103</span><span class="comment"> * Timer_event_emitter supplies those things.</span></div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno">  104</span><span class="comment"> *</span></div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno">  105</span><span class="comment"> * ### How to use ###</span></div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno">  106</span><span class="comment"> * Construct Timer_event_emitter.  This will start an idle thread (and it will remain totally idle with the</span></div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno">  107</span><span class="comment"> * sole exception of a pipe-write executing when a timer actually fires).</span></div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno">  108</span><span class="comment"> *</span></div>
<div class="line"><a id="l00109" name="l00109"></a><span class="lineno">  109</span><span class="comment"> * Call create_timer().  This just returns a totally normal `flow::util::Timer` to be saved in the</span></div>
<div class="line"><a id="l00110" name="l00110"></a><span class="lineno">  110</span><span class="comment"> * `sync_io`-pattern-implementing object.  create_timer() merely associates the `*this` thread with that</span></div>
<div class="line"><a id="l00111" name="l00111"></a><span class="lineno">  111</span><span class="comment"> * timer, so that when `Timer::async_wait(F)` eventually causes `F()` to execute, it will execute `F()`</span></div>
<div class="line"><a id="l00112" name="l00112"></a><span class="lineno">  112</span><span class="comment"> * in that thread.</span></div>
<div class="line"><a id="l00113" name="l00113"></a><span class="lineno">  113</span><span class="comment"> *</span></div>
<div class="line"><a id="l00114" name="l00114"></a><span class="lineno">  114</span><span class="comment"> * Call create_timer_signal_pipe() (for each timer one plans to use).  This creates a pipe; saves both ends</span></div>
<div class="line"><a id="l00115" name="l00115"></a><span class="lineno">  115</span><span class="comment"> * inside `*this`; and returns a pointer to the read-end.  The `sync_io`-pattern object saves this,</span></div>
<div class="line"><a id="l00116" name="l00116"></a><span class="lineno">  116</span><span class="comment"> * including so that it can pass the associated Native_handle (FD) to #Event_wait_func, whenever it</span></div>
<div class="line"><a id="l00117" name="l00117"></a><span class="lineno">  117</span><span class="comment"> * begins a timer-wait.</span></div>
<div class="line"><a id="l00118" name="l00118"></a><span class="lineno">  118</span><span class="comment"> *</span></div>
<div class="line"><a id="l00119" name="l00119"></a><span class="lineno">  119</span><span class="comment"> * Use the `Timer` completely as normal, including `Timer::expires_after()` to schedule and reschedule</span></div>
<div class="line"><a id="l00120" name="l00120"></a><span class="lineno">  120</span><span class="comment"> * the firing time... with one exception:</span></div>
<div class="line"><a id="l00121" name="l00121"></a><span class="lineno">  121</span><span class="comment"> *</span></div>
<div class="line"><a id="l00122" name="l00122"></a><span class="lineno">  122</span><span class="comment"> * Instead of the usual `Timer::async_wait()`, call instead timer_async_wait(), which takes:</span></div>
<div class="line"><a id="l00123" name="l00123"></a><span class="lineno">  123</span><span class="comment"> *   - Pointer to the `Timer`.  `*this` will `-&gt;async_wait(F)` on that `Timer`.</span></div>
<div class="line"><a id="l00124" name="l00124"></a><span class="lineno">  124</span><span class="comment"> *   - Pointer to the associated pipe read-end.  `*this` will use it as a key to determine the associated</span></div>
<div class="line"><a id="l00125" name="l00125"></a><span class="lineno">  125</span><span class="comment"> *     write-end.  `F()` will simply perform the 1-byte-write to that write-end.</span></div>
<div class="line"><a id="l00126" name="l00126"></a><span class="lineno">  126</span><span class="comment"> *</span></div>
<div class="line"><a id="l00127" name="l00127"></a><span class="lineno">  127</span><span class="comment"> * (timer_async_wait() is, basically, a convenience.  We could instead have had create_timer_signal_pipe()</span></div>
<div class="line"><a id="l00128" name="l00128"></a><span class="lineno">  128</span><span class="comment"> * return both the read-end and write-end; and had the `*this` user memorize both and itself do</span></div>
<div class="line"><a id="l00129" name="l00129"></a><span class="lineno">  129</span><span class="comment"> * the `Timer::async_wait()`, with the handler writing to the write-end.  It is nicer to keep that stuff</span></div>
<div class="line"><a id="l00130" name="l00130"></a><span class="lineno">  130</span><span class="comment"> * to `*this`.)</span></div>
<div class="line"><a id="l00131" name="l00131"></a><span class="lineno">  131</span><span class="comment"> *</span></div>
<div class="line"><a id="l00132" name="l00132"></a><span class="lineno">  132</span><span class="comment"> * Lastly, when #Event_wait_func `on_active_ev_func()` informs the `sync_op`-pattern-implementing object</span></div>
<div class="line"><a id="l00133" name="l00133"></a><span class="lineno">  133</span><span class="comment"> * of a timer-associated FD being readable, it must read the byte off the pipe by calling</span></div>
<div class="line"><a id="l00134" name="l00134"></a><span class="lineno">  134</span><span class="comment"> * consume_timer_firing_signal().  (Again, it&#39;s just a convenience.  We could have had the user object</span></div>
<div class="line"><a id="l00135" name="l00135"></a><span class="lineno">  135</span><span class="comment"> * read the byte themselves.  It is nicer to keep the protocol inside `*this`.)</span></div>
<div class="line"><a id="l00136" name="l00136"></a><span class="lineno">  136</span><span class="comment"> *</span></div>
<div class="line"><a id="l00137" name="l00137"></a><span class="lineno">  137</span><span class="comment"> * ### Thread safety note ###</span></div>
<div class="line"><a id="l00138" name="l00138"></a><span class="lineno">  138</span><span class="comment"> * A given `*this` itself has boring thread-safety properties: you may not call a non-`const` method</span></div>
<div class="line"><a id="l00139" name="l00139"></a><span class="lineno">  139</span><span class="comment"> * while calling another method.  That, however, is unlikely to be interesting.</span></div>
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno">  140</span><span class="comment"> *</span></div>
<div class="line"><a id="l00141" name="l00141"></a><span class="lineno">  141</span><span class="comment"> * It is not safe to concurrently call `timer_async_wait(&amp;T)`, where `T` is a `Timer`, with any other</span></div>
<div class="line"><a id="l00142" name="l00142"></a><span class="lineno">  142</span><span class="comment"> * method of `T`.  You can think, in this context, of `timer_async_wait(&amp;T)` as being equivalent to</span></div>
<div class="line"><a id="l00143" name="l00143"></a><span class="lineno">  143</span><span class="comment"> * `T-&gt;async_wait()`.</span></div>
<div class="line"><a id="l00144" name="l00144"></a><span class="lineno">  144</span><span class="comment"> */</span></div>
<div class="line"><a id="l00145" name="l00145"></a><span class="lineno"><a class="line" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html">  145</a></span><span class="keyword">class </span><a class="code hl_class" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html">Timer_event_emitter</a> :</div>
<div class="line"><a id="l00146" name="l00146"></a><span class="lineno">  146</span>  <span class="keyword">public</span> flow::log::Log_context,</div>
<div class="line"><a id="l00147" name="l00147"></a><span class="lineno">  147</span>  <span class="keyword">private</span> boost::noncopyable <span class="comment">// And non-movable.</span></div>
<div class="line"><a id="l00148" name="l00148"></a><span class="lineno">  148</span>{</div>
<div class="line"><a id="l00149" name="l00149"></a><span class="lineno">  149</span><span class="keyword">public</span>:</div>
<div class="line"><a id="l00150" name="l00150"></a><span class="lineno">  150</span>  <span class="comment">// Types.</span></div>
<div class="line"><a id="l00151" name="l00151"></a><span class="lineno">  151</span><span class="comment"></span> </div>
<div class="line"><a id="l00152" name="l00152"></a><span class="lineno">  152</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00153" name="l00153"></a><span class="lineno">  153</span><span class="comment">   * Object representing the read end of IPC mechanism, where readable status indicates the associated</span></div>
<div class="line"><a id="l00154" name="l00154"></a><span class="lineno">  154</span><span class="comment">   * timer_async_wait() call has resulted in the timer firing.  Formally the `*this` user shall perform only</span></div>
<div class="line"><a id="l00155" name="l00155"></a><span class="lineno">  155</span><span class="comment">   * the following operations on such an object R, after obtaining it from create_timer_signal_pipe():</span></div>
<div class="line"><a id="l00156" name="l00156"></a><span class="lineno">  156</span><span class="comment">   *   - Load your Asio_waitable_native_handle `E` via `E.assign(Native_handle(R.native_handle())`</span></div>
<div class="line"><a id="l00157" name="l00157"></a><span class="lineno">  157</span><span class="comment">   *     or equivalent.</span></div>
<div class="line"><a id="l00158" name="l00158"></a><span class="lineno">  158</span><span class="comment">   *   - Call `Event_wait_func`, passing in `&amp;E`, just ahead of Timer_event_emitter::timer_async_wait().</span></div>
<div class="line"><a id="l00159" name="l00159"></a><span class="lineno">  159</span><span class="comment">   *   - Call `consume_timer_firing_signal(&amp;R)` in the handler for the so-registered-via-`Event_wait_func`</span></div>
<div class="line"><a id="l00160" name="l00160"></a><span class="lineno">  160</span><span class="comment">   *     event (meaning, if the timer indeed fired).</span></div>
<div class="line"><a id="l00161" name="l00161"></a><span class="lineno">  161</span><span class="comment">   */</span></div>
<div class="line"><a id="l00162" name="l00162"></a><span class="lineno"><a class="line" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a1533a54927a64579fda02c61ec94b735">  162</a></span>  <span class="keyword">using </span><a class="code hl_typedef" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a1533a54927a64579fda02c61ec94b735">Timer_fired_read_end</a> = boost::asio::readable_pipe;</div>
<div class="line"><a id="l00163" name="l00163"></a><span class="lineno">  163</span> </div>
<div class="line"><a id="l00164" name="l00164"></a><span class="lineno">  164</span>  <span class="comment">// Constructors/destructor.</span></div>
<div class="line"><a id="l00165" name="l00165"></a><span class="lineno">  165</span><span class="comment"></span> </div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno">  166</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno">  167</span><span class="comment">   * Constructs emitter, creating idle thread managing no timers.</span></div>
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno">  168</span><span class="comment">   *</span></div>
<div class="line"><a id="l00169" name="l00169"></a><span class="lineno">  169</span><span class="comment">   * @param logger_ptr</span></div>
<div class="line"><a id="l00170" name="l00170"></a><span class="lineno">  170</span><span class="comment">   *        Logger to use for subsequently logging.</span></div>
<div class="line"><a id="l00171" name="l00171"></a><span class="lineno">  171</span><span class="comment">   * @param nickname_str</span></div>
<div class="line"><a id="l00172" name="l00172"></a><span class="lineno">  172</span><span class="comment">   *        Human-readable nickname of the new object, as of this writing for use in `operator&lt;&lt;(ostream)` and</span></div>
<div class="line"><a id="l00173" name="l00173"></a><span class="lineno">  173</span><span class="comment">   *        logging only.</span></div>
<div class="line"><a id="l00174" name="l00174"></a><span class="lineno">  174</span><span class="comment">   */</span></div>
<div class="line"><a id="l00175" name="l00175"></a><span class="lineno">  175</span>  <span class="keyword">explicit</span> <a class="code hl_function" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a8a4720c9fc5ecb15ce2efee16b4c3cee">Timer_event_emitter</a>(flow::log::Logger* logger_ptr, <a class="code hl_typedef" href="namespaceipc_1_1util.html#ae6ac47812a90d1287c61e0b7de7bc4f5">String_view</a> nickname_str);</div>
<div class="line"><a id="l00176" name="l00176"></a><span class="lineno">  176</span> </div>
<div class="line"><a id="l00177" name="l00177"></a><span class="lineno">  177</span>  <span class="comment">// Methods.</span></div>
<div class="line"><a id="l00178" name="l00178"></a><span class="lineno">  178</span><span class="comment"></span> </div>
<div class="line"><a id="l00179" name="l00179"></a><span class="lineno">  179</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00180" name="l00180"></a><span class="lineno">  180</span><span class="comment">   * Creates idle timer for use with timer_async_wait() subsequently.  It is associated with the thread</span></div>
<div class="line"><a id="l00181" name="l00181"></a><span class="lineno">  181</span><span class="comment">   * started in the ctor, meaning completion handlers shall execute in that thread.</span></div>
<div class="line"><a id="l00182" name="l00182"></a><span class="lineno">  182</span><span class="comment">   *</span></div>
<div class="line"><a id="l00183" name="l00183"></a><span class="lineno">  183</span><span class="comment">   * Formally, behavior is undefined if T is the returned timer or one moved-from it, and one invokes</span></div>
<div class="line"><a id="l00184" name="l00184"></a><span class="lineno">  184</span><span class="comment">   * `T.async_wait()` on it; you must use `timer_async_wait(&amp;T, ...)` instead.  You may call other `T`</span></div>
<div class="line"><a id="l00185" name="l00185"></a><span class="lineno">  185</span><span class="comment">   * methods; in particular the `expires_*()` mutators will be useful.  You may in particular call</span></div>
<div class="line"><a id="l00186" name="l00186"></a><span class="lineno">  186</span><span class="comment">   * `T.cancel()` and destroy `T`.  However see timer_async_wait() regarding the effects of these various</span></div>
<div class="line"><a id="l00187" name="l00187"></a><span class="lineno">  187</span><span class="comment">   * methods/calls.</span></div>
<div class="line"><a id="l00188" name="l00188"></a><span class="lineno">  188</span><span class="comment">   *</span></div>
<div class="line"><a id="l00189" name="l00189"></a><span class="lineno">  189</span><span class="comment">   * @return See above.</span></div>
<div class="line"><a id="l00190" name="l00190"></a><span class="lineno">  190</span><span class="comment">   */</span></div>
<div class="line"><a id="l00191" name="l00191"></a><span class="lineno">  191</span>  flow::util::Timer <a class="code hl_function" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#aab9cd218457e4fa5ce3bb6e1b59542ee">create_timer</a>();</div>
<div class="line"><a id="l00192" name="l00192"></a><span class="lineno">  192</span><span class="comment"></span> </div>
<div class="line"><a id="l00193" name="l00193"></a><span class="lineno">  193</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00194" name="l00194"></a><span class="lineno">  194</span><span class="comment">   * Creates, and internally stores, an IPC mechanism instance intended for use with a given create_timer()-returned</span></div>
<div class="line"><a id="l00195" name="l00195"></a><span class="lineno">  195</span><span class="comment">   * `Timer`; returns pointer to the read-end of this mechanism.</span></div>
<div class="line"><a id="l00196" name="l00196"></a><span class="lineno">  196</span><span class="comment">   *</span></div>
<div class="line"><a id="l00197" name="l00197"></a><span class="lineno">  197</span><span class="comment">   * The returned object is valid through `*this` lifetime.</span></div>
<div class="line"><a id="l00198" name="l00198"></a><span class="lineno">  198</span><span class="comment">   *</span></div>
<div class="line"><a id="l00199" name="l00199"></a><span class="lineno">  199</span><span class="comment">   * @see #Timer_fired_read_end doc header for instructions on the acceptable/expected uses of the returned object.</span></div>
<div class="line"><a id="l00200" name="l00200"></a><span class="lineno">  200</span><span class="comment">   *</span></div>
<div class="line"><a id="l00201" name="l00201"></a><span class="lineno">  201</span><span class="comment">   * @return See above.</span></div>
<div class="line"><a id="l00202" name="l00202"></a><span class="lineno">  202</span><span class="comment">   */</span></div>
<div class="line"><a id="l00203" name="l00203"></a><span class="lineno">  203</span>  <a class="code hl_typedef" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a1533a54927a64579fda02c61ec94b735">Timer_fired_read_end</a>* <a class="code hl_function" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#ad2124aadd5025490aedf16958db4599c">create_timer_signal_pipe</a>();</div>
<div class="line"><a id="l00204" name="l00204"></a><span class="lineno">  204</span><span class="comment"></span> </div>
<div class="line"><a id="l00205" name="l00205"></a><span class="lineno">  205</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00206" name="l00206"></a><span class="lineno">  206</span><span class="comment">   * To be used on a timer `T` returned by create_timer(), this is the replacement for the usual</span></div>
<div class="line"><a id="l00207" name="l00207"></a><span class="lineno">  207</span><span class="comment">   * `T.async_wait(F)` call that loads a completion handler to execute at the expiration time.  Instead of</span></div>
<div class="line"><a id="l00208" name="l00208"></a><span class="lineno">  208</span><span class="comment">   * supplying the completion handler `F()`, one supplies a read-end returned by create_timer_signal_pipe();</span></div>
<div class="line"><a id="l00209" name="l00209"></a><span class="lineno">  209</span><span class="comment">   * when the timer fires a payload shall be written to the associated write-end.  You must call</span></div>
<div class="line"><a id="l00210" name="l00210"></a><span class="lineno">  210</span><span class="comment">   * your #Event_wait_func, passing it an Asio_waitable_native_handle, wrapping the handle in the same `*read_end`,</span></div>
<div class="line"><a id="l00211" name="l00211"></a><span class="lineno">  211</span><span class="comment">   * ahead of this timer_async_wait() call.</span></div>
<div class="line"><a id="l00212" name="l00212"></a><span class="lineno">  212</span><span class="comment">   *</span></div>
<div class="line"><a id="l00213" name="l00213"></a><span class="lineno">  213</span><span class="comment">   * You may not call timer_async_wait() on the same `*read_end` until one of the following things occurs:</span></div>
<div class="line"><a id="l00214" name="l00214"></a><span class="lineno">  214</span><span class="comment">   *   - The timer fires; and the user event loop&#39;s async-wait indeed wakes up and passes that to your object;</span></div>
<div class="line"><a id="l00215" name="l00215"></a><span class="lineno">  215</span><span class="comment">   *     and your object therefore invokes `consume_timer_firing_signal(read_end)`.</span></div>
<div class="line"><a id="l00216" name="l00216"></a><span class="lineno">  216</span><span class="comment">   *   - The async-wait is *successfully* canceled: `T.cancel()` or `T.expires_*()` returns non-zero (in fact, 1).</span></div>
<div class="line"><a id="l00217" name="l00217"></a><span class="lineno">  217</span><span class="comment">   *</span></div>
<div class="line"><a id="l00218" name="l00218"></a><span class="lineno">  218</span><span class="comment">   * @param timer</span></div>
<div class="line"><a id="l00219" name="l00219"></a><span class="lineno">  219</span><span class="comment">   *        The timer to arm.</span></div>
<div class="line"><a id="l00220" name="l00220"></a><span class="lineno">  220</span><span class="comment">   * @param read_end</span></div>
<div class="line"><a id="l00221" name="l00221"></a><span class="lineno">  221</span><span class="comment">   *        A value returned by create_timer_signal_pipe().</span></div>
<div class="line"><a id="l00222" name="l00222"></a><span class="lineno">  222</span><span class="comment">   */</span></div>
<div class="line"><a id="l00223" name="l00223"></a><span class="lineno">  223</span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a838497cd832da97bf1d52a7b8a85734c">timer_async_wait</a>(flow::util::Timer* timer, <a class="code hl_typedef" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a1533a54927a64579fda02c61ec94b735">Timer_fired_read_end</a>* read_end);</div>
<div class="line"><a id="l00224" name="l00224"></a><span class="lineno">  224</span><span class="comment"></span> </div>
<div class="line"><a id="l00225" name="l00225"></a><span class="lineno">  225</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00226" name="l00226"></a><span class="lineno">  226</span><span class="comment">   * Must be called after a timer_async_wait()-triggered timer fired, before invoking that method for the same</span></div>
<div class="line"><a id="l00227" name="l00227"></a><span class="lineno">  227</span><span class="comment">   * `Timer` again.  It reads the small payload that was written at the time of the timer&#39;s firing (in</span></div>
<div class="line"><a id="l00228" name="l00228"></a><span class="lineno">  228</span><span class="comment">   * the internal-IPC mechanism used for this purpose).</span></div>
<div class="line"><a id="l00229" name="l00229"></a><span class="lineno">  229</span><span class="comment">   *</span></div>
<div class="line"><a id="l00230" name="l00230"></a><span class="lineno">  230</span><span class="comment">   * @param read_end</span></div>
<div class="line"><a id="l00231" name="l00231"></a><span class="lineno">  231</span><span class="comment">   *        See timer_async_wait() and create_timer_signal_pipe().</span></div>
<div class="line"><a id="l00232" name="l00232"></a><span class="lineno">  232</span><span class="comment">   */</span></div>
<div class="line"><a id="l00233" name="l00233"></a><span class="lineno">  233</span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a80a0549f49fafc358763e9325c31256b">consume_timer_firing_signal</a>(<a class="code hl_typedef" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a1533a54927a64579fda02c61ec94b735">Timer_fired_read_end</a>* read_end);</div>
<div class="line"><a id="l00234" name="l00234"></a><span class="lineno">  234</span><span class="comment"></span> </div>
<div class="line"><a id="l00235" name="l00235"></a><span class="lineno">  235</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00236" name="l00236"></a><span class="lineno">  236</span><span class="comment">   * Returns nickname as passed to ctor.</span></div>
<div class="line"><a id="l00237" name="l00237"></a><span class="lineno">  237</span><span class="comment">   * @return See above.</span></div>
<div class="line"><a id="l00238" name="l00238"></a><span class="lineno">  238</span><span class="comment">   */</span></div>
<div class="line"><a id="l00239" name="l00239"></a><span class="lineno"><a class="line" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a96f26e369ac1289b0a684d12f6bf07c3">  239</a></span>  <span class="keyword">const</span> std::string&amp; <a class="code hl_function" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a96f26e369ac1289b0a684d12f6bf07c3">nickname</a>() <span class="keyword">const</span>;</div>
<div class="line"><a id="l00240" name="l00240"></a><span class="lineno">  240</span> </div>
<div class="line"><a id="l00241" name="l00241"></a><span class="lineno">  241</span>  <span class="comment">// Data.</span></div>
<div class="line"><a id="l00242" name="l00242"></a><span class="lineno">  242</span><span class="comment"></span> </div>
<div class="line"><a id="l00243" name="l00243"></a><span class="lineno">  243</span><span class="comment">  /// Nickname as passed to ctor.</span></div>
<div class="line"><a id="l00244" name="l00244"></a><span class="lineno"><a class="line" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a63c1e77a76775134b5a6d4725d58be81">  244</a></span><span class="comment"></span>  <span class="keyword">const</span> std::string <a class="code hl_variable" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a63c1e77a76775134b5a6d4725d58be81">m_nickname</a>;</div>
<div class="line"><a id="l00245" name="l00245"></a><span class="lineno">  245</span> </div>
<div class="line"><a id="l00246" name="l00246"></a><span class="lineno">  246</span><span class="keyword">private</span>:</div>
<div class="line"><a id="l00247" name="l00247"></a><span class="lineno">  247</span>  <span class="comment">// Data.</span></div>
<div class="line"><a id="l00248" name="l00248"></a><span class="lineno">  248</span><span class="comment"></span> </div>
<div class="line"><a id="l00249" name="l00249"></a><span class="lineno">  249</span><span class="comment">  /// The thread where (only) timer-firing events (from create_timer()-created `Timer`s) execute.</span></div>
<div class="line"><a id="l00250" name="l00250"></a><span class="lineno"><a class="line" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#ad17e799f7c36c4c0cbc858637377f456">  250</a></span><span class="comment"></span>  flow::async::Single_thread_task_loop <a class="code hl_variable" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#ad17e799f7c36c4c0cbc858637377f456">m_worker</a>;</div>
<div class="line"><a id="l00251" name="l00251"></a><span class="lineno">  251</span><span class="comment"></span> </div>
<div class="line"><a id="l00252" name="l00252"></a><span class="lineno">  252</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00253" name="l00253"></a><span class="lineno">  253</span><span class="comment">   * The readers (never null) returned by create_timer_signal_pipe().  The order is immaterial, as</span></div>
<div class="line"><a id="l00254" name="l00254"></a><span class="lineno">  254</span><span class="comment">   * this is just a place #m_signal_pipe_writers map keys can point into.  Wrapped into `unique_ptr`, so that</span></div>
<div class="line"><a id="l00255" name="l00255"></a><span class="lineno">  255</span><span class="comment">   * the address of a #Timer_fired_read_end (as returned by create_timer_signal_pipe()) remains valid until `*this`</span></div>
<div class="line"><a id="l00256" name="l00256"></a><span class="lineno">  256</span><span class="comment">   * dies.</span></div>
<div class="line"><a id="l00257" name="l00257"></a><span class="lineno">  257</span><span class="comment">   */</span></div>
<div class="line"><a id="l00258" name="l00258"></a><span class="lineno"><a class="line" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#afafdfa9e2c522cd3e12b4f1915f83b56">  258</a></span>  std::vector&lt;boost::movelib::unique_ptr&lt;Timer_fired_read_end&gt;&gt; <a class="code hl_variable" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#afafdfa9e2c522cd3e12b4f1915f83b56">m_signal_pipe_readers</a>;</div>
<div class="line"><a id="l00259" name="l00259"></a><span class="lineno">  259</span><span class="comment"></span> </div>
<div class="line"><a id="l00260" name="l00260"></a><span class="lineno">  260</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00261" name="l00261"></a><span class="lineno">  261</span><span class="comment">   * Stores the write-ends of the pipes created in create_timer_signal_pipe(), indexed by</span></div>
<div class="line"><a id="l00262" name="l00262"></a><span class="lineno">  262</span><span class="comment">   * pointer to their respective read-ends.  timer_async_wait() can therefore look-up a write-end</span></div>
<div class="line"><a id="l00263" name="l00263"></a><span class="lineno">  263</span><span class="comment">   * based on the read-end pointer it gave to the user, which the user must pass-to timer_async_wait().</span></div>
<div class="line"><a id="l00264" name="l00264"></a><span class="lineno">  264</span><span class="comment">   */</span></div>
<div class="line"><a id="l00265" name="l00265"></a><span class="lineno">  265</span>  boost::unordered_map&lt;<a class="code hl_typedef" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a1533a54927a64579fda02c61ec94b735">Timer_fired_read_end</a>*,</div>
<div class="line"><a id="l00266" name="l00266"></a><span class="lineno"><a class="line" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#ac2e6652bed4a80239d57a7fad2bab47c">  266</a></span>                       boost::movelib::unique_ptr&lt;boost::asio::writable_pipe&gt;&gt; <a class="code hl_variable" href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#ac2e6652bed4a80239d57a7fad2bab47c">m_signal_pipe_writers</a>;</div>
<div class="line"><a id="l00267" name="l00267"></a><span class="lineno">  267</span>}; <span class="comment">// class Timer_event_emitter</span></div>
<div class="line"><a id="l00268" name="l00268"></a><span class="lineno">  268</span> </div>
<div class="line"><a id="l00269" name="l00269"></a><span class="lineno">  269</span><span class="comment">// Free functions: in *_fwd.hpp.</span></div>
<div class="line"><a id="l00270" name="l00270"></a><span class="lineno">  270</span> </div>
<div class="line"><a id="l00271" name="l00271"></a><span class="lineno">  271</span>} <span class="comment">// namespace ipc::util::sync_io</span></div>
<div class="ttc" id="aclassipc_1_1util_1_1sync__io_1_1Timer__event__emitter_html"><div class="ttname"><a href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html">ipc::util::sync_io::Timer_event_emitter</a></div><div class="ttdoc">An object of this type, used internally to implement sync_io-pattern objects that require timer event...</div><div class="ttdef"><b>Definition:</b> <a href="timer__ev__emitter_8hpp_source.html#l00145">timer_ev_emitter.hpp:148</a></div></div>
<div class="ttc" id="aclassipc_1_1util_1_1sync__io_1_1Timer__event__emitter_html_a1533a54927a64579fda02c61ec94b735"><div class="ttname"><a href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a1533a54927a64579fda02c61ec94b735">ipc::util::sync_io::Timer_event_emitter::Timer_fired_read_end</a></div><div class="ttdeci">boost::asio::readable_pipe Timer_fired_read_end</div><div class="ttdoc">Object representing the read end of IPC mechanism, where readable status indicates the associated tim...</div><div class="ttdef"><b>Definition:</b> <a href="timer__ev__emitter_8hpp_source.html#l00162">timer_ev_emitter.hpp:162</a></div></div>
<div class="ttc" id="aclassipc_1_1util_1_1sync__io_1_1Timer__event__emitter_html_a63c1e77a76775134b5a6d4725d58be81"><div class="ttname"><a href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a63c1e77a76775134b5a6d4725d58be81">ipc::util::sync_io::Timer_event_emitter::m_nickname</a></div><div class="ttdeci">const std::string m_nickname</div><div class="ttdoc">Nickname as passed to ctor.</div><div class="ttdef"><b>Definition:</b> <a href="timer__ev__emitter_8hpp_source.html#l00244">timer_ev_emitter.hpp:244</a></div></div>
<div class="ttc" id="aclassipc_1_1util_1_1sync__io_1_1Timer__event__emitter_html_a80a0549f49fafc358763e9325c31256b"><div class="ttname"><a href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a80a0549f49fafc358763e9325c31256b">ipc::util::sync_io::Timer_event_emitter::consume_timer_firing_signal</a></div><div class="ttdeci">void consume_timer_firing_signal(Timer_fired_read_end *read_end)</div><div class="ttdoc">Must be called after a timer_async_wait()-triggered timer fired, before invoking that method for the ...</div><div class="ttdef"><b>Definition:</b> <a href="timer__ev__emitter_8cpp_source.html#l00123">timer_ev_emitter.cpp:123</a></div></div>
<div class="ttc" id="aclassipc_1_1util_1_1sync__io_1_1Timer__event__emitter_html_a838497cd832da97bf1d52a7b8a85734c"><div class="ttname"><a href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a838497cd832da97bf1d52a7b8a85734c">ipc::util::sync_io::Timer_event_emitter::timer_async_wait</a></div><div class="ttdeci">void timer_async_wait(flow::util::Timer *timer, Timer_fired_read_end *read_end)</div><div class="ttdoc">To be used on a timer T returned by create_timer(), this is the replacement for the usual T....</div><div class="ttdef"><b>Definition:</b> <a href="timer__ev__emitter_8cpp_source.html#l00081">timer_ev_emitter.cpp:81</a></div></div>
<div class="ttc" id="aclassipc_1_1util_1_1sync__io_1_1Timer__event__emitter_html_a8a4720c9fc5ecb15ce2efee16b4c3cee"><div class="ttname"><a href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a8a4720c9fc5ecb15ce2efee16b4c3cee">ipc::util::sync_io::Timer_event_emitter::Timer_event_emitter</a></div><div class="ttdeci">Timer_event_emitter(flow::log::Logger *logger_ptr, String_view nickname_str)</div><div class="ttdoc">Constructs emitter, creating idle thread managing no timers.</div><div class="ttdef"><b>Definition:</b> <a href="timer__ev__emitter_8cpp_source.html#l00030">timer_ev_emitter.cpp:30</a></div></div>
<div class="ttc" id="aclassipc_1_1util_1_1sync__io_1_1Timer__event__emitter_html_a96f26e369ac1289b0a684d12f6bf07c3"><div class="ttname"><a href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#a96f26e369ac1289b0a684d12f6bf07c3">ipc::util::sync_io::Timer_event_emitter::nickname</a></div><div class="ttdeci">const std::string &amp; nickname() const</div><div class="ttdoc">Returns nickname as passed to ctor.</div></div>
<div class="ttc" id="aclassipc_1_1util_1_1sync__io_1_1Timer__event__emitter_html_aab9cd218457e4fa5ce3bb6e1b59542ee"><div class="ttname"><a href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#aab9cd218457e4fa5ce3bb6e1b59542ee">ipc::util::sync_io::Timer_event_emitter::create_timer</a></div><div class="ttdeci">flow::util::Timer create_timer()</div><div class="ttdoc">Creates idle timer for use with timer_async_wait() subsequently.</div><div class="ttdef"><b>Definition:</b> <a href="timer__ev__emitter_8cpp_source.html#l00039">timer_ev_emitter.cpp:39</a></div></div>
<div class="ttc" id="aclassipc_1_1util_1_1sync__io_1_1Timer__event__emitter_html_ac2e6652bed4a80239d57a7fad2bab47c"><div class="ttname"><a href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#ac2e6652bed4a80239d57a7fad2bab47c">ipc::util::sync_io::Timer_event_emitter::m_signal_pipe_writers</a></div><div class="ttdeci">boost::unordered_map&lt; Timer_fired_read_end *, boost::movelib::unique_ptr&lt; boost::asio::writable_pipe &gt; &gt; m_signal_pipe_writers</div><div class="ttdoc">Stores the write-ends of the pipes created in create_timer_signal_pipe(), indexed by pointer to their...</div><div class="ttdef"><b>Definition:</b> <a href="timer__ev__emitter_8hpp_source.html#l00266">timer_ev_emitter.hpp:266</a></div></div>
<div class="ttc" id="aclassipc_1_1util_1_1sync__io_1_1Timer__event__emitter_html_ad17e799f7c36c4c0cbc858637377f456"><div class="ttname"><a href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#ad17e799f7c36c4c0cbc858637377f456">ipc::util::sync_io::Timer_event_emitter::m_worker</a></div><div class="ttdeci">flow::async::Single_thread_task_loop m_worker</div><div class="ttdoc">The thread where (only) timer-firing events (from create_timer()-created Timers) execute.</div><div class="ttdef"><b>Definition:</b> <a href="timer__ev__emitter_8hpp_source.html#l00250">timer_ev_emitter.hpp:250</a></div></div>
<div class="ttc" id="aclassipc_1_1util_1_1sync__io_1_1Timer__event__emitter_html_ad2124aadd5025490aedf16958db4599c"><div class="ttname"><a href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#ad2124aadd5025490aedf16958db4599c">ipc::util::sync_io::Timer_event_emitter::create_timer_signal_pipe</a></div><div class="ttdeci">Timer_fired_read_end * create_timer_signal_pipe()</div><div class="ttdoc">Creates, and internally stores, an IPC mechanism instance intended for use with a given create_timer(...</div><div class="ttdef"><b>Definition:</b> <a href="timer__ev__emitter_8cpp_source.html#l00046">timer_ev_emitter.cpp:46</a></div></div>
<div class="ttc" id="aclassipc_1_1util_1_1sync__io_1_1Timer__event__emitter_html_afafdfa9e2c522cd3e12b4f1915f83b56"><div class="ttname"><a href="classipc_1_1util_1_1sync__io_1_1Timer__event__emitter.html#afafdfa9e2c522cd3e12b4f1915f83b56">ipc::util::sync_io::Timer_event_emitter::m_signal_pipe_readers</a></div><div class="ttdeci">std::vector&lt; boost::movelib::unique_ptr&lt; Timer_fired_read_end &gt; &gt; m_signal_pipe_readers</div><div class="ttdoc">The readers (never null) returned by create_timer_signal_pipe().</div><div class="ttdef"><b>Definition:</b> <a href="timer__ev__emitter_8hpp_source.html#l00258">timer_ev_emitter.hpp:258</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_1_1sync__io_html"><div class="ttname"><a href="namespaceipc_1_1util_1_1sync__io.html">ipc::util::sync_io</a></div><div class="ttdoc">Contains common code, as well as important explanatory documentation in the following text,...</div><div class="ttdef"><b>Definition:</b> <a href="detail_2util__fwd_8hpp_source.html#l00208">util_fwd.hpp:209</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_ae6ac47812a90d1287c61e0b7de7bc4f5"><div class="ttname"><a href="namespaceipc_1_1util.html#ae6ac47812a90d1287c61e0b7de7bc4f5">ipc::util::String_view</a></div><div class="ttdeci">flow::util::String_view String_view</div><div class="ttdoc">Short-hand for Flow's String_view.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00115">util_fwd.hpp:115</a></div></div>
<div class="ttc" id="autil__fwd_8hpp_html"><div class="ttname"><a href="util__fwd_8hpp.html">util_fwd.hpp</a></div></div>
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